WASHINGTON –Today, the U.S. Environmental Protection Agency (EPA) released phase II of the National Stormwater Calculator and Climate Assessment Tool package. The updated calculator includes future climate vulnerability scenarios.

The calculator, a part of President Obama’s Climate Change Action Plan, is a desktop application that estimates the annual amount of stormwater runoff from a specific location. The Calculator now includes changes in seasonal precipitation levels, the effects of more frequent high-intensity storms, and changes in evaporation rates based on validated Intergovernmental Panel on Climate Change climate change scenarios.

“Climate change threatens our health, our economy, and our environment,” said Gina McCarthy, EPA Administrator. “As part of the President’s Climate Action Plan, this tool will help us better prepare for climate impacts by helping build safer, sustainable, and more resilient water infrastructure”

The updated calculator includes climate models that can be incorporated into the calculation of stormwater runoff. This adds future climate scenarios to last year’s phase I release, which included local soil conditions, slope, land cover, historical rainfall records.

Users can enter any U.S. location and select different scenarios to learn how specific green infrastructure changes, including inexpensive changes such as rain barrels and rain gardens, can reduce stormwater runoff. This information shows users how adding green infrastructure, which mimics natural processes, can be one of the most cost-effective ways to reduce stormwater runoff.

Every year billions of gallons of raw sewage, trash, household chemicals, and urban runoff flow into our streams, rivers and lakes. Polluted stormwater runoff can adversely affect plants, animals, and people. It also negatively impacts our economy – from closed beaches to decreased fishing in polluted areas. Green infrastructure can reduce the damage caused by climate change by improving water quality in streams and rivers, protecting groundwater sources, and enhancing recreational activities. Using the calculator to choose the best green infrastructure options for an area is an innovative and efficient way to promote healthy waters and support sustainable communities.